Constant current transformer actuated control mechanism



May 16, 1933. l. E. MOCABE 1,909,371

CONSTANT CURRENT TRANSFORMER ACTUATED CONTROL MECHANISM Filed July 7, 1950 4 Sheets-Sheet 1 I I IL L 2,7 l g u \u l I l I fly I v INVENTOR 1 [RA E. n was ATTORNEY E. M CABE 1,909,371 CONSTANT CURRENT TRANSFORMER ACTUATED CONTROL MECHANISM May 16, 1933.

Filed July '7, 1930 I 4 Sheets-Sheet 2 INVENTOR BY RA ELI/l CABE ATTORNEY I May 16, 1933. E MCCABE 1,909,371

CONSTANT CURRENT TRANSFORMER ACTUATED CONTROL MECHANISM Filed July 7,'. 1930 4 Sheets-Sheet 3 INVENTOR IRA E'.. in CAbE. BY

ATTORN EY l. E, MCCABE May 16, .1933.

CONSTANT CURRENT TRANSFORMER ACTUATED CONTROL MECHANISM Filed July '7, 1950 4 Sheets-Sheet 4 POSITION DUE/N6 IGNITION PER O NORMAL Pos/T/o/v I NORMAL RUNN/Nc; POSITION INVENTOR IRA E. M CASE ATTORNEY Patented May 16, 1933 PATENT OFFICE IRA E. MCCABE, OF CHICAGO, ILLINOIS CONSTANT CURRENT TRANSFORMER ACTUATED CONTROL MECHANISM Application filed July 7,1930. Serial No. 465,882.

This invention relates to improvements in electrical control devices especially adapted for electrically operated or actuated fluid fuel burner mechanisms and more particularly to the mechanism of a constant current transformer actuated control system such as disclosed in this applicants prior copending application Serial No. 446,573, filed April 23, 1930, which matured into Patent 1,881,321 of October 4, 1932.

This application is a further development or refinement of certain parts of the operating mechanism as disclosed in said prior copendingapplication. It is an object of this invention to so construct certain parts to insure the normal operation under such conditions as the necessity of the particular burner mechanism employing a burner motor requiring a heavy current demand at its starting sufficient to reduce momentarily the commercial voltage passing through the ignition switch of the control, which would otherwise deenergize the primary floating coil and cause it to drop before the motor in starting reaches its normal running speed, and where residual magnetism might momentarily hold the armature against the holding magnet after the breaking of the circuit, therethrough by the opening of the stack safety switch, as well as providing positive means for insuring the opening of the ignition switch after the energizing of the holding magnet upon the closing of the circuit therethrough by the moved, similar to Figure 1 of said prior copending application, showing the improved construction of parts as contemplated by this invention, the parts being illustrated in the closing of the stack safety switch upon the positions assumed when the burner is cold or when the burner motor is idle.

Figure 2 is a view similar to Figure 1 illustrating the positions assumed by the respective parts when the burner isnormally runmug.

Figure 3 is a detail view in front elevation of the improved yoke or operative connection between the primary coil of the constant current transformer and the lifting lever of the actuating mechanism, the primary coil shown 111 its lower position assumed when deenergized.

Figure 4 is a view in side elevation of Fig ure 3, illustrating in dot and dash lines the positions of the parts assumed after the primary coil is energized and floating.

Figure 5 is a detail view in front elevation illustrating the construction of the spring and counterweight of the ignition switch carrier plate.

Figures 6, 7, 8 and 9 are diagrams indicating positions assumed and circuits established when the circuit is first closed to start operation, position during the ignition period, normal running position, and normal idle position, respectively.

WVith the exceptions of the particular constructions hereinafter described the parts are constructed and operate as disclosed in said 30 prior copending application and therefore it is thought necessary only to describe in detail the improved constructions and their cooperation in general with the other parts of the control in order to show clearly the improve- 35 ments over the corresponding parts in said prior Patent 1,881,321 of October 4, 1932.

Figures 1 and 2 show a panel 1 for mounting the control mechanism which includes a constant current transformer in which the rectangular core 2 is mounted on the rear side of the panel 1. The secondary coil 3 of the constant current transformer is stationary and rests upon the bottom portions of the rectangular core 2, as shown,.while the primary coil 4 is mounted thereabove and is adapted to float thereabove when energized.

The respective terminals 5 of the secondary coil, only one being seen in front elevation, are adapted to be connected in the ignition circuit. The respective terminals of the primary coil, not shown, are connected to the thermostat closes the circuit, to start the operation of the burner mechanism, the primary coil 4 of the constant current transformer in this control device will be energized and caused to float above the stationary secondary coil 3 at the same time setting up a constant flow of current through the ignition circuit 5, shown in Figures 6 to 9 inclusive.

The switch operating and actuating mechanism, as in said prior copending application, is mounted upon a base plate 7 supported on the panel 1 spaced apart a suflicient distance therefrom to allow movement of the primary coil therebehind. A yoke 8 including right angular side extensions 9 provided with pivots 10 mounted in bearings 11 struck up from the panel 1 is adapted to tilt about its pivots at the rear of the base plate 7, shown also in Figures 3 and 4. The upper portion of each side 9 is extended beyond the respective pivots to form an engaging finger 12. The yoke 8 is so mounted that its pivots 10 are approximately in line with the top of the primary coil when deenergized and resting upon the secondary coil 3. Engaging members 13 are secured diametrically opposite each other upon the upper surface of the primary coil 4 so that when the primary coil 4 is deenergized the engaging members 13 engage the engaging fingers 12 and tilt the yoke upward about its pivots, as shown in full lines in Figure 4. When the primary coil 4 is energized andfloats above the secondary coil 3 the yoke 8 is free to tilt in the opposite direction about its pivots.

In said prior copending application, the floatin of the primary coil freed a yoke to bodily move upward and in so doing impart a rotative movement to a lifting lever adapted to free certain other parts of the control mechanism to be caused to function.

In the present construction, the floating of the primary coil 4 frees the yoke 8 to rotate in a downward direction, which movement is imparted to a lifting lever 14, corresponding to the lifting lever in said prior copending application to perform a corresponding function, in the following manner. The lifting lever 14 is pivoted at 15 upon the base plate 7 and that part which extends to the left of the pivot is enlarged to increase its weight on that side and is also provided with a bearin 16 adapted to slidably receive a connecting rod 17 secured at its lower end to a struck up portion 18 of the yoke 8, which rod is provided at its upper end above the bearing 16 with an adjusting nut 19 and is surrounded between the under side of the bearing 16 and struck up portion 18 by a coil spring 20 of sufficient strength to normally maintain the distance between the bearing and portion 18 constant, so that when the primary coil floats and frees the yoke the weight of the yoke will, through connecting rod 17, be transmitted to the enlarged end of the lifting lever 14 and will be suflicient to rotate it about its pivot 15, and cause that portion of the lifting lever to the right of its pivot to move in an upward direction, the same as the corresponding lifting lever moved in said prior copending application upon the floating of the primary coil in that device. Likewise, when the primary coil 4 is deenergized it drops upon the stationary secondary coil 3 and in so doing the engaging members 13 thereon engage the engaging fingers 12 of the yoke 8 and rotate the front of the yoke 8 upward whereupon through the rod 17 and spring 20, the lifting lever is I()..

tated in the opposite direction, and normally will result in a shut down or recycling of. the control the same as in said priorv application.

It has been found that in some types of fluid fuel burning mechanisms it is necessary to employ a type of motor making an initial heavy current demand in starting which is sufficient to'reduce the commercial voltage passing through the control until the motor is running normally. In the device disclosed in said prior copending application, if this initial reduction of voltage was suflieient to deenergize the primary coil, and in certain types of motors the said reduction is sufficient to produce such a result, which must necessarily occur before the running motor circuit-had been completed by the establish ment of combustion, a shut down would occur. at i In order to compensate for such a reduction in voltage, a dash pot 21, preferably an air dash pot such as illustrated, is provided and mounted on the panel 1 above the left hand enlarged portion of the lifting lever 14, the piston 22 of the dash pot 21 being connected by the rod 23 to a stud 24 carried on the opposite side of the lifting lever -14 preferably in line with and adjacent the bearing 16.

In the type of motor referred to the. reduction in voltage is but momentary and in a short space of time the voltage becomes normal as the motor reaches its normal running. By the above described construction when a momentary reduction in voltage occurs "and if the primary coil drops to tilt the yoke 8, the coil spring takes up the shock and the dash pot, being connected to the lifting lever 14, resists and slows up the rotation of the lifting leversufliciently to allow the reener gizing and floating of the primary coil as the motor load becomes normal before the extension 30 adapted to engage the locking carrier plate 26, mounting a motor switch.

M S, and actuating member 27 and a bell crank locking lever 28, all pivoted upon the base plate to function in the same manner as the corresponding parts in said prior copending application. Also a holding magnet E with armature 29 pivoted at 29" having an lever 28 are shown mounted in the same manner as in said prior copending application. The. actuating member 27 is rotated about its pivot by link 31 and bi-metallic member 32, and the. ignition switch carrier plate 25 is moved to close the ignition switch thereby through the spring pressed link 27*, as well as the locking lever 28 caused to lock'the motor switch carrier plate 26 with the motor switch in closed position by the energization of the holding magnet E and through members 30 and 39 to open the ignition switch, as-

disclosed in said prior copending application. The lifting lever 14 isprovided onthe right of its pivot with a pin 33 adapted in the upper position to be held by the locked motor switch carrier plate 26; with a stud.

34 therebeyond, adapted to pass through aperture in the base plate, to limit the pawl 36, all similar andfor similar functions as in said prior copending application.

upward and downward amount of movement of the lever; and therebeyond with a pivoted From the foregoing it is seen that when the burner mechanism is idle, the primary coil 4. is dead and its weight upon the engaging fingers 12 has caused the yoke through spring 20 to rotate thelifting lever 14 to lift the piston 22 to the end of its stroke in the dash pot 21 and the parts are in the position of the corresponding parts as disclosed in, the cold positionin said prior co pending application, with the ignition switch. closed and the running motor switch open. The room thermostat T calls for heat by closing. The circuit through the ignition switch is closed thereby and the primary coil energized and begins to float releasing the yoke 8 to begin the depression of the left hand end .of the lifting lever 14. In case of a momentary deenergization of the primary coil 4, before the motor switch is locked in closed position, its full weight falls upon the engaging fingers 12 and the impetus of theyoke to rotate the lifting lever 14 is absorbed by, first, the compression of spring 20 and then'bythe dash pot 21 a the spring expands sothat, as the motor load becomes normal, the coil 4 will'fioat again beforethe lifting lever 14 has rotated enough to cause the mechanism to shut down, whereby the. control operates normally to first close the running motorswitch and then open the ignition switch. In so doing the motor switch carrier 26 as it is locked in closed position will engage the pin'33 to support the coil 4 when it becomes deenergized, as in said prior copending application. When the room thermostat opens as the desired temperature is reached, the motor switch carrier plate 26 is unlocked and the weight of the coil 4 acting upon the yoke 8 will cause the freed lifting lever 14 to assume the cold position.

Certain types of burner mechanisms require the ignition elements to be so heated that when ignition occurs the elements are within the flame of the burning fuel and, un-

less the ignitioncircuit is broken promptly after ignition of the fuel occurs, the ignition elements are subjected not only to the heat of the flame but also the heat generated by the passage through them of the ignition circuit. The continuous action of the combined heats may have a deteriorating action upon the ignition elements and to prevent the possibility of such combined heat destroying or making the elements inoperative this invention contemplates providing means whereby the'ignition circuit is opened as soon combustion chamber, all as described insaid priorcopending application.

The opening of the ignition circuit by the holding magnet E is accomplished in the following manner: A shoulder 37 is provided at the free end of arm 30 of the armature 29 whereby the shoulder, upon upward movement of the arm when the holding magnet is energized, will not only engage the Weighted horizontal .arm 38 of the locking bell crank lever 28 but also the underside of the counterweight 39 and as it is pushed up, will, through movement of the pin 42 on the counterweight 39 in the notch 43 of the switch carrier, tilt the carrier, opening the ignition switch during the normal operation, and thereafter hold it open until the is engaged therewith by the pin 42 on the plate 39 received in the notch 43 of the carrier plate 25. This pin 42 is adapted to be engaged bythe pawl 36 under certain conditions and functionas in said prior copending application. v

In order to insure a quick and positive re"- lease of the armature 29 irrespective of any residual magnetism that may exist upon the deenergizing of the holding magnet E, and consequently insuring the prompt release of the motor switch carrier plate 26 from engagement with the locking lever 28, the counterweight plate 39 is provided on the underside with a strong spring member 40. lVhen the magnet is energized the shoulder 37 pushes upward the counterweight until it engages the fixed stud 41 upon the base plate 7 and further movement of the magnet armature results in the compression of the spring member 40, so, upon deenergizing the magnet the pressure of the spring lO imparts an initial impetus to free the armature 29 to unlock the motor switch carrier plate 26.

In said prior copending application the horizontal arm of the bell crank locking lever is weighted to rotate the locking lever to unlock themotor switch carrier plate when the holding magnet is deenergized and requires a manual rotation in the opposite direction to reset the device and a manual reset which upon rotation causes a. swinging arm to engage the armature arm to rotate against the holding magnet to lift the weighted portion of the locking lever. As a further refinement, this invention-contemplates the omission of the manual reset just described and rotation of the armature by providing the free end of the horizontal arm 38 of the locking lever with vertical outwardly curved portion 44 adapted to project through a slot in the side casing wall and be engaged by the,

hand to manually rotate the locking lever to reset the device.

From the above description it is seen that this improved control mechanism while performing all the functions of that disclosed in said prior copending application and in which most of the parts are of similar construction, in addition thereto, it compensates for the employment of burner mecha nisms employing motors having a heavy starting load: insures a prompt and positive freeing of the magnet armature 'upon deenergization to allow the ignition switch to close and the motor switch to open; and provides a simple and positive reset'forming a part of the locking lever.

From the diagrams illustrated in Figures 6 to 9 inclusive, it is readily seen that, as illustrated in Figure 6, when the room thermostatl closes a circuit is closed from the source of electricity through the normally closed boiler control B, room thermostat T. normally closed ignition switch 6 and through the primary coil 4 of the constant current transformer and back to the commercial line, as indicated in heavy lines. The closing of this circuit energizes the secondary coil 3 of the constant current transformer -which not only causes the primary coil to which passes through lei-metallic member. 32

' gized, the bi-metallic member 32 becomes deformed and, as shown in Figure 7, causes the motor switch M S to close, thereby setting up a circuit from the commercial line from the binding post adjacent the room thermostat through the motor switch M S and through the motor back to the commercial line. When the fuel is ignited the thermally actuated safety switch S responds thereto and closes, thereby closing a circuit from the binding post adjacent the room thermostat T through the holding magnet E back to the commercial line without disturbing the motor circuit already established. The closing of the circuit through the holding magnet actuates its armature to open the ignition switch 6, whereby the primary coil 4 is deenergized and likewise the ignition circuit, at the same time the armature of the holding magnet E locks the motor switch M S in closed position and thereby through stud 33 supports the primaryv coil 4. This is the normal running position, as illustrated in Figure 8.

Upon the deenergizing of the ignition circult, the bi-metallic member 32 cools and exerts tension upon the member 27 to normally open the motor switch which is held closed as long as the holding magnet E is energized. Upon opening of the circuit through the room thermostat the holding magnet E is deenergized which allows the motor switch M S to be unlocked, so that the same will be thrown by member 27 to open position and this movement of member 27 through link 27 a closes the ignition switch 6, as shown in Figure 9.

What I claim is:

1. A control mechanism for an oil burner having an electric motor, including a constant current transformer having a stationary and a movable coil, a switch in the motor circuit normally held in open position, a switch in the primary circuit of the transformer normally closed, whereby the closing of the circuit to the control energizes the transformer and causes one coil to float above the other, means operative as a result of.

to the expiration of said predetermined time.

to open said motor switch, and additional means to retard the action of the deenergized coil during said predetermined time.

2. In a device of the character disclosed, including a burner having a motor and an electrically operative igniter, a switch in the motor circuit normally open, an ignition switch normally closed, means operable upon mechanism closing the circuit through the ignition switch to close the motor switch to operate the burner mechanism and thereafter permit the breaking of the circuit through the ignition switch,-means controlled by the normal the motor switch in closed position during the continued normal operation of said including a normally open thermaltswitch operative to close upon ignition of the fuel, a holding magnet in the circuit of said last named switch, an armature actuated by energizing said holding magnet to lock the motor switch closed, and

open the ignition switch, and said thermalswitch opening to deenergize said magnet and release said armature to release sald motor switch to open and said ignition switch to close when the burner flame fails, and additional means to prevent residual mag- =netism retarding the unlocking of the motor switch and freeing the ignition switch upon deenergization of the holding magnet including a spring acting upon the lock engaging arm of the armature.

3. In a device of the character disclosed,

including a burner having a motor and an normally open thermal switch adapted toclose upon ignition of the fuel,-a holding magnet in the circuit of said last named switch, an armature actuated by energizing said holding magnet to lock the motor switch closed and lift the counter weight of the snap action mechanism, to open and hold open the ignition switch, said thermal switch opening to deenergize said magnet and release said armature to release said motor switch to open and said ignition switch to close when the burner flame fails, and additional means to prevent residual magnetism retarding the unlockingof the motor and ignition switches upon deenergization of the holding magnet including a spring upon said counter,

weight acting upon the lock'engaging arm of the armature.

4. In a device of the character disclosed, including a burner having a motor and an electrically operable igniter, aswitch in the motor circuit normally open, an ignition switch normally closed including a switch ope-rated mechanism and counter weight, means operable upon clodng the circuit through the ignition switch to close the motor switch to operate the burner mechanism and thereafter permit the breaking of the circuit through the ignition switch, means controlled by the normal operation (if the burner mechaoperation of. the burner mechanism to look nism to lock the motor switch in closed position during the continued normal operation of said mechanism including a normally open ture actuated by energizing said holding magnet to lift the counter weight of the switch operated mechanism to open and hold open the ignition switch, and to lock in closed position the motor switch and said thermal switch openin to deenergize said magnet and release sai armature to release said ignition switch to close and said motor switch to open when the burner flame fails. 5. In an ignition and control means for fluidfuel burning devices having a motor and an electrically operable igniter including a motor switch, an ignition switch, and a constant current transformer, in circuit with said igniter and ignition switch, including a stationary low voltage coil with a bimetallic actuating means in circuit with said coil and with said igniter, means connected to said actuating means to operate to close the motor switch and open the ignition switch, a floating high voltage coil means operated by the weight thereof arranged 'to cause the motor switch to be closed by the bimetallic means when said coil is floating and to prevent the motor switch from closing when it fails to float, means including an air 'dashpot for delaying the sinking action of the floating coil from operating to open the motor switch during a limited period, a holding magnet and means operated thereby arranged to lock the motor switch in either on or-ofl position as it may be at the time the holding magnet is energized ,and .to also open the ignition switch and hold it open as long as it is energized. v

6. In a device of the character disclosed, including a burner having a burner motor and an electrically operable igniter, a switch a in the motor circuit normally open,"an ignition switch normally closed including a switch operating mechanism and counterweight, meansoperable upon closing the circuit through the ignition switch to close the .motor switch to operate the burner mechanism and thereafter permit the'breaking ofthe circuit through the ignition swich, means controlled by the normal operation of the.

burner mechanism to lock the motor switch in closed position during the continued normal operation of said mechanism including a normally open thermal switch adapted to close upon ignition of the fuel, a holding magnet in the circuit of said named switch, an armature actuated by energizing said holding magnet to lift the counterweight of the switch operated mechanism to open and hold open the ignition switch and to lock in closed position the motor switch, and

said thermal switch opening to deenergize said magnet and release said armature to release said ignition switch to close and said motor switch to open when the burner flame fails, and upon a momentary interrup- 1 tion of current to the device when the burner mechanism is normally operating, the momentary deenergization of the holding magnet releases said armature to allow the motor and ignition switch operating means to return the motor switch to open position and the ignition switch to closed position and the immediate resumption of current re-energizes the holding magnet to actuate the armature to hold open the motor switch and lift the ignition switch counterweight to tilt the ignition switch to open position whereupon combustion ceases and the thermal switch opens to de-energize the holding magnet to release the armature to free the motor switch and release the ignition switch counterweight to allow the ignition switch to return to closed position and the control recycles in going through the movement of a normal start. so IRA E. MCCABE. 

